We intend to study the mechanisms of storage and selective translation of messenger RNA's during germination of Mucor racemosus sporangiospores. We have recently established the existence of stored messenger RNA in spores of Mucor. We now plan to identify the form or structure in which it is stored. We also plan to study whether the stored messenger RNA is different in composition from that synthesized during germination and whether any unique gene products are translated off the stored message during the morphogenesis. We anticipate that the messenger RNA is sequestered in ribonucleoprotein particles prior to translation. We plan to characterize the properties and composition of these particles and to monitor any changes in their composition and/or intracellular location. Such changes, if they occur, may represent a mechanism for implementing differential gene expression in the development of this organism. The findings of this study will be of potential medical importance because the fungus Mucor is an opportunistic pathogen which can cause a rare, through severe, form of mucormycosis in which the brain is invaded via the nasal sinuses and death inevitably ensues. The organism generally enters the body in the form of dormant spores, which once in the tissue germinate into the pathogenic vegetative form. The organism is similar in its dimorphic habit and pathogenicity to the causative agents of histoplasmosis and blastomycosis, potentially lethal diseases endemic to the Mississippi River Valley. Understanding the biochemical mechanisms controlling development in this fungus may allow us to alleviate the invasiveness and/or pathogenicity of these microorganisms.